Frequently Asked Questions

The Emerald Ash Borer (EAB) is an exotic beetle from Asia that was accidentally introduced into North America prior to 2002. Its larvae feed on and kill ash trees. It is present in parts of Illinois, Indiana, Michigan, Ohio, Pennsylvania, West Virginia, Maryland, and Virginia. It was found in southeast Missouri in July 2008.

Ash trees are affected by several diseases and insects. Ash trees throughout the state exhibit dying branches and/or decline and some may show signs of heavy woodpecker damage. This may or may not be due to the Emerald Ash Borer. Positive identification of the insect is required to document its presence by sending a specimen to the state entomologists listed below.

Find out more about the Emerald Ash Borer. An educational campaign has been launched to explain the threat from this beetle and prevent its spread to Missouri. This fact sheet is a part of this effort.

1. Where did the Emerald Ash Borer (EAB) come from?
The native range of EAB is eastern Russia, northern China, Japan and Korea.
2. When was EAB first discovered in North America?
EAB was first identified in southeast Michigan in 2002. It likely arrived several years earlier.
3. How did it get to North America?
Although no one knows exactly how the insect gained admittance to the US, it most likely arrived in solid wood packaging materials that originated from Asia. This could include ash wood used for crating, pallets, or stabilizing cargo in ships.
4. Where is EAB now?
As of July 2008, EAB had been found in Illinois, Indiana, Michigan, Ohio, Pennsylvania, West Virginia, Maryland, Virginia and Missouri.  Current map of EAB distribution in the USA
5. How does EAB harm ash trees?
The larval stage of EAB feeds under the bark of trees, cutting off the flow of water and nutrients. Branches of heavily infested trees will begin to die, usually near the top of the crown and progressing downward. The bark may crack directly over larval galleries.  Adult beetles chew characteristic “D”-shaped exit holes as they leave former feeding sites below the bark. Infested trees gradually die over a two to four year period.
6. Which trees are susceptible?
All sizes and even very healthy ash trees can be killed. All of Missouri's native ash trees (green, white, blue and pumpkin ash), as well as many horticultural cultivars (cultivated varieties of ash or hybrids between species of ash), are susceptible to EAB infestation. Research studies are ongoing to test for resistance in various cultivars with the hope that some may survive an infestation. Identify your trees
7. How important are ash trees to Missouri?
Information from community tree inventories indicates that overall, ash trees comprise about 14 percent of street trees in Missouri communities and over 21 percent of trees in urban parks (data compiled by Missouri Department of Conservation, 2005). The percentages rise to well over 30 percent in some parks and residential subdivisions. In natural forest stands, ash trees comprise about 3 percent of total trees (USDA Forest Service, Forest Inventory and Analysis data).
8. What does EAB look like?
The adult beetle is dark metallic green, bullet-shaped, and about one-half inch long (7 to 13 mm) and 1/8 inch (3 mm) wide. While the back of the insect is an iridescent, metallic green, the underside is a bright, emerald green. The body is narrow and elongated, and the head is flat. The eyes are kidney shaped and usually black.  The EAB larva is white and flat, has distinctive bell shaped segments and can grow up to 1.2 inches (30 mm) long.
9. How does EAB spread?
EAB moves short distances by flying and longer distances through movement of infested ash.  Adults typically do not fly far from where they emerge, but this depends on the availability of food (ash trees).  In Michigan, studies have shown that the vast majority of insects fly only several hundred yards from where they emerge.  EAB is most commonly spread long distances through the movement of infested firewood, nursery stock or ash logs.  Transport of infested firewood remains an ongoing concern for movement of EAB and other forest pests.
10. What is being done about EAB?
There is a national effort to limit the spread and impact of EAB.  A national plan, coordinated by the U.S. Department of Agriculture, Animal Plant Health Inspection Service (APHIS), guides what federal, state and local officials must do to manage this insect.  Infested areas are quarantined, which means that selected materials such as firewood from deciduous trees, ash nursery stock, and ash logs may not be moved out of infested areas.  Where outlying infestations are detected, large numbers of infested ash trees are sometimes cut and destroyed to reduce EAB populations.  Research is underway in many universities and government agencies to find better ways to detect and manage this pest.
11. What is being done in Missouri?
The Missouri Department of Agriculture, Missouri Department of Conservation and the Missouri Department of Natural Resources have initiated an education and outreach program on the EAB and other pest species that are transported in firewood. A poster was produced in August 2006 and is being posted in campgrounds and recreational areas to alert the public to this threat.

A Missouri Conservationist article in March 2007 described the threat from EAB and other “hitchhiking bugs” that can be transported in firewood.

Annual surveys to detect the arrival of EAB are conducted by the Missouri Department of Conservation, Missouri Department of Agriculture, and US Forest Service at selected state parks, public and commercial campgrounds, and high-risk urban sites.

In 2008, a Missouri Emerald Ash Borer Action Plan was completed by the Missouri Department of Agriculture, Missouri Department of Conservation, Missouri Department of Natural Resources, and other state, federal, and private partners.
12. Is there anything I can do now to protect the ash trees in my yard from EAB?
Keeping trees vigorous and healthy by proper pruning, mulching, watering and avoiding wounding helps them resist insect attacks.  No insecticides are 100% effective against emerald ash borer attacks.  Not bringing firewood from other states is one of the best ways to avoid bringing home unwanted tree pests.
13. If I have ash in my woods, should I be doing anything?
At this time, you need not change your scheduled timber management activities.
14.  Are there any natural enemies of the emerald ash borer? 
Yes, scientists have observed parasitic wasps attacking egg or larval stages of the emerald ash borer in its native land.  Efforts are underway to determine if these wasps could be safe and effective controls of EAB in America.  Unfortunately, this process is time-consuming and these wasps may not be available for effective use in current EAB containment efforts.  Other studies are testing various fungi and bacteria that infect beetles for possible use as “natural insecticides.”
15. Is ash still a viable choice when considering what to plant in my yard?
In general, having a diversity of tree species in your yard, on your street or in your community is your best defense against all tree health problems.  Plant no more than 10 percent of any one tree species in your yard.  Because of the severe nature of the EAB threat, the wisest choice at this time is not to plant any ash trees.
16. What can I do to help?
Educate yourself on how to recognize signs and symptoms of EAB.